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SOME ASPECTS OF PARASITIC GASTROENTERITIS OF SHEEP. *
Author(s) -
McL. Gordon Hugh
Publication year - 1950
Publication title -
australian veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.382
H-Index - 59
eISSN - 1751-0813
pISSN - 0005-0423
DOI - 10.1111/j.1751-0813.1950.tb04861.x
Subject(s) - epidemiology , disease , outbreak , medicine , environmental health , pathology
SUMMARY The nature of parasitic gastro‐enteritis of sheep is discussed from a number of aspects. The necessity is stressed for the separation of “parasitic gastro‐enteritis” into various disease entities before it is possible to understand its pathogenesis, treatment and prevention. The more important gastro‐intestinal helminthiases of sheep in Australia are discussed as to reasons for their importance, symptomatology, epidemiological considerations with special reference to seasonal occurrence, and diagnosis. The less important parasites are discussed briefly. The extent and significance of parasitic gastro‐enteritis in sheep in Australia is examined with comments on the number of sheep involved and the nature and range of losses which may occur. The effects of sub‐clinical levels of infestation are discussed and their general contribution to unthriftiness in sheep is stressed. The influence of the complex effects of parasitic infestations and the variations in their intensity from year to year combine to make for inefficiency of intermittent control measures and necessitate continuous control measures based on epidemiological information. Some information is presented on the costs of control measures, chiefly regarding costs of anthelminties. The cost of an “epidemiological” plan of treatment is given. The uses, testing and efficiency of anthelmintics are discussed with emphasis on preventive or strategic use as opposed to curative use. The application o f anthelmintics for greatest preventive effect depends on epidemiological information to determine the strategic and tactical timing of treatments. Results of trials of anthelmintics under outbreak conditions are presented to place the value of anthelmintics in proper perspective. Preventive measures are considered in the light of indications for points of attack in the life‐cycle and with regard for difficulties in early diagnosis and complex seasonal fluctuations in parasite populations. Long term plans may be necessary for some parasitic diseases, notably oesophagos‐tomiasis due to Oe. columbianum. A knowledge of the ways in which resistance may be influenced is capable of making a large contribution to the development of control measures, despite the absence of precise understanding of the mechanism of resistance. The special case of the “Self‐Cure” phenomenon is discussed further and doubt is cast oil the hypothesis suggested in a previous paper (Gordon, 1948a).